The seat opened when incumbent Democratic Rep. Donna Edwards left to run for Maryland’s open Senate seat. She lost in the primary to Rep. Chris Van Hollen, now the senator-elect after his general election victory Tuesday night.

A sprawling suburban district with a black-majority population, Maryland’s 4th District stretches from the eastern and southern borders of Washington, D.C., to the outskirts of Annapolis.

Brown was familiar to most voters, having previously served two terms as state lieutenant governor under Democratic Gov. Martin O’Malley. But he suffered a surprise defeat in the 2014 gubernatorial election at the hands of Republican Larry Hogan.

He bounced back in April, winning the 4th District’s Democratic primary, which was tantamount to winning the seat, considering there are more than four times as many registered Democratic voters as registered Republicans in the district.

Now a retired colonel in the Army Reserve, Brown was deployed to Iraq for about 10 months in 2004 and 2005 with a civil affairs unit and ended up as an adviser to the Iraqi ministry of displacement and migration, working in tandem with the Red Crescent and United Nations agencies on refugee and resettlement problems.